HERE'S a moment early in the series premiere of "Entourage," the new HBO comedy, which is likely to cause some cringing among certain young Hollywood stars and the posses who trail them. Vincent Chase, a vapid but great-looking star on the rise, played by Adrian Grenier, is being pestered by his best-buddy-slash-aspiring-manager Eric (Kevin Connolly) to read a script for a movie pitched as " `Die Hard' at Disneyworld."

Vince can't understand why. He never finished the script for his last film. "I didn't even know who the killer was till I saw the thing," he laughs.

"There's nothing in the show that's not something that one of us has experienced," said Doug Ellin, the show's creator. "Mark was very clear that we don't want to make a fake version of this. He wanted it to be real."

The Mark of which he speaks is the actor Mark Wahlberg, who not only serves as an executive producer of the show, but the model for Vince — and through some combination of these two roles, as Hollywood's latest tattler-sociologist. In the first two episodes alone, the show takes swipes at sycophantic agents, promiscuous groupies, pseudo-virginal pop stars, dimwitted star siblings and, of course, immature, insecure, unprepared movie stars.

But it's the funny, painful exploration of the phenomenon known as the entourage that sets the show apart from other industry satires. Like the fictional Vince and the real Mr. Wahlberg, many young stars surround themselves with a ring of friends who travel with them, hang out with them, often live with them. Everyone gets something from the arrangement: the new star gets the comfort of people who have known him for more than five minutes, and the friends get the fun of his reflected glow. But it's also a profoundly awkward, inherently inequitable relationship: dependent on their old friend's fame, money and connections, the buddies end up essentially working for the star, often in petty capacities, and inevitably getting on his nerves. But they go along with it, for such are the rewards of reflected celebrity. On "Entourage," that dynamic is played out for full humiliation: most of Vince's friends are practically manservants, doing his driving and cooking; one is reduced to telling a girl: "Come on, make out with me. I'll show you where Vince eats breakfast." (It works.)

Mark Wahlberg based the story on his own experience as a young star, when he routinely partied until dawn, romanced untold numbers of starlets, tussled with rival entourages (including Madonna's) and built a tight inner circle made up of other Boston natives and an assortment of oddballs he collected along the way. For these friends, having their most parasitic moments replayed for a national audience can't be all that comfortable, but when Mr. Wahlberg championed the project, they went along with it, for such are the rewards of reflected celebrity: several of them are credited as producers or consultants.

THE biggest question about "Entourage" may be why Mr. Wahlberg, a firmly established star with both box office and critical hits to his name, would decide to expose the often embarrassing circumstances of his own social life to millions of HBO subscribers. It's as if Tom Cruise were starring in a fable about Hollywood secrecy, or Jennifer Aniston and Brad Pitt were writing a script about high-profile coupledom. After all, almost no one in Hollywood knows more about entourages than Mr. Wahlberg. He has headed his own posse for the better part of the last 15 years, as he transitioned from being the bad-side-of-Boston rapper Marky Mark to the respected, bankable star of movies like "Boogie Nights," "Three Kings" and "Planet of the Apes." Through it all, Mr. Wahlberg, 33, has prided himself on his eclectic mix of hangers-on.

As he explained in a recent interview in his suite in the Trump International Hotel and Towers in Manhattan, Mr. Wahlberg sees these companions as useful, even necessary. "My thing was always that having the people I have around keeps me grounded," he said. "If you're an actor and you're working on films on a pretty regular basis, you're going to have people around you constantly anyways, so why not make it people that you like, that you're comfortable with? It just always made more sense to me. If you're going to have a driver, why not have someone you know and that you like?"

At the same time, Mr. Wahlberg is well aware of how some entourages work, mining stardom for treats they could never afford on their own. "You have the yes men and you have the no men," Mr. Wahlberg said, mentioning guys who would praise his talent and then in the next breath demand, "Buy this Maybach," a top of the line luxury car, or, "How come we don't have the new Rolls?"

The characters on the show are based directly on real-life cronies of Mr. Wahlberg's. Turtle, the rotund, crassly funny, baseball-cap wearing driver (played by Jerry Ferrara) is based on a struggling rapper named Donkey who performs under the name Murder One. The character of Johnny Drama (played by Kevin Dillon, brother of the former teen idol Matt), is Vince's half-brother, his cook and an also-ran actor. He is modeled in large part on John Alves (whose nickname is the same as Mr. Dillon's character's), a bodybuilding security guard-slash-spiritual guide who was tapped by Mr. Wahlberg's brother, Donnie, to keep his kid brother out of trouble. (At 16, Mr. Wahlberg was convicted of assault and served 50 days in a state penitentiary.) It was Mr. Alves, who had done a couple of episodes of obscure television shows, whom Mr. Wahlberg credits with getting him into acting. In the show, Johnny Drama is nakedly, pathetically jealous of Vince's effortless success.

"I'm a lot like this guy, I've had an up and down career," said Mr. Dillon, 38. "And I've definitely crashed on Matt's couch a number of times, and he's picked up a lot of checks."

The character of Eric, the sensible one who acts as a go-between with the star's agent, is largely based on Steve Levinson, Mr. Wahlberg's actual manager and another of the show's executive producers, and Eric Weinstein, a middle-aged Bronx native, who first met the star on the set of "The Basketball Diaries" in the mid 1990's, when Mr. Wahlberg was new to Hollywood and searching for confidantes. On the show, the character of Eric is the smart, sensible friend and the only vaguely moral presence. He regularly clashes with Vince's agent, Ari Jacobs, played by Jeremy Piven.

Unlike the members of the entourage, Ari is a seasoned Hollywood professional, whose relationship with Vince involves a comparatively simple kind of mutual exploitation. He is also the most brutal — and brutally funny — character on the show, a screaming, bullying, womanizing 10-percenter. Mr. Wahlberg says the character is also a loving — yes, loving — tribute to Ari Emanuel, Mr. Wahlberg's famously brash agent at the Endeavor Agency. (Mr. Emanuel says that he is "amused" by the portrayal.) In yet another insider twist, Mr. Emanuel used to represent Mr. Piven, who says the character is also a more general take on the kind of "high-strung, fast-talking, $40 million-before-you're-40 guy" common in Hollywood. "I've had people come up and say, `Oh my god, you totally got him — how did you do that?' and they're talking about someone I never heard of," Mr. Piven said.

He added that he thought that the show's realism came from Mr. Wahlberg's experiences as a flavor-of-the-month star who managed to parlay early attention into a durable career. "It's true that old saying: you write what you know," he said. "And if anyone's been in the belly of the beast, it's Mark Wahlberg."

THE real reason Mr. Wahlberg has chosen to expose and lampoon his entourage may rest in the logic of the entourage itself. In a bizarre extension of the usual posse dynamic, the show is providing jobs, and even a bit of exposure, for these longtime friends and hangers-on. In fact, the original idea for the series came from Mr. Weinstein, who started to film a documentary about the odd assortment of characters who still surround Mr. Wahlberg. The star liked the idea, but preferred to turn his posse into a fictional group, in order to more brutally satirize himself, his friends and the industry that made him a star.

Mr. Weinstein, who had never developed a television show, was more than happy to offer up his sometimes-humiliating experiences for the delectation of HBO viewers. In yet another example of an opportunity available only through Mr. Wahlberg, Mr. Weinstein received an associate producer credit on the show, while Mr. Alves (the real Johnny Drama) is billed as a consultant. But even more than the credential, these posse members — who for years have held Mr. Wahlberg's doors and fetched his drycleaning — are finally having a moment in the spotlight, even if it's coming at their own expense.

Mr. Weinstein, 49, says he has no problem with viewers laughing at the entourage — "The show shows how close we all are," he says — and feels proud of the work he does for his boss. "It's neverending," he said. "I do construction, I'm the estate manager, travel agent, I read scripts. It's a team effort."

Mr. Wahlberg says his entourage, and the industry, are looking forward to the show. "Some people are a little nervous, and they should be, because we're not going to pull any punches," he said. "If you get it and you want to be in on it, cool. If not, you're probably going to be on the butt end of a couple of jokes."

As tough as "Entourage" is so far, both Mr. Wahlberg and Mr. Ellin say things are just going to get more cringe-inducing. "We've definitely held back," Mr. Ellin said. "We will get more outrageous."

And Mr. Wahlberg promises to continue mining his life, in real time, for material. As an example, he mentioned that his mother — who was at the previous evening's starry New York premiere for the show — might have a cameo as Vince's mother in an upcoming episode. The idea is for her to ride in a car with the pot-smoking entourage members and, as a result, end up with a contact high. How, pray tell, did this idea come to him? "Well," said Mr. Wahlberg with a sheepish grin. "She was in the car with us last night."